We are not able to modify role name.
Release : 15.9.1
Component : CA PPM SAAS RESOURCE MANAGEMENT
For this scenario it was because the Role Name had the Enter Once option checked.
Go to the Resource Object
Admin => Studio / Object
Resource Object - Open it
Click on Views Tab
Go to the line that says Role Labor and click on the associated Fields link, (5th line)
Open the Role Name field.
Check to see if the option Enter Once is checked on the Role Name
If it is uncheck it.
Then you can edit the role name.
Make the field Enter Once again if you do not want the field to be changed.